Carburetor



July 29, 1958 A. A. VUYLSTEKE 2,845,257

. CARBURETOR'I 7 Filed Nov. 14, 1955 INVENTOR @ZiWQZ gkkk BYOQQQM ATTORNEY CARBURETUR Arthur A. Vuylsteke, Detroit, Mich assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application November 14, 1955, Serial No. 546,573

6 Claims. (Cl. 26l--76) The present invention relates to mixing means and more particularly to means for continuously mixing one fluid with another fluid.

It is often desirable to mix one fluid with another fluid in some predetermined proportions and by means of a continuous process. One means by which this may be accomplished is to place a metering orifice or so-called jet in a stream of primary fluid. Thus as the primary fluid flows past the jet, the secondary fluid will be drawn from the jet and mixed with the primary fluid. If the jet is properly positioned in the stream of primary fluid, the flow will cause the volume of secondary fluid so discharged to be in some predetermined proportion to the volume of the primary fluid. Although the proportions between the two fluids will be substantially constant for any given set of circumstances, in the event there is a wide variation in the volume of the flow of the primary fluid, the proportions between the primary and secondary fluids may vary somewhat. In addition, it is also frequently desirable to vary the proportions between the two fluids. For example in an internal combustion engine, a combustible charge may be formed by placing a fuel jet in a stream of air flowing through the induction system so as to atomize the liquid fuel into the air. Although the air-fuel ratio of the charge may remain substantially constant over the major portion of the engine operating range, there are some circumstances such as operation at subnormal temperatures, periods of acceleration, full load operation etc., when it may be desirable to change the air-fuel ratio. In the carburetors employed heretofore, it has been necessary to employ complicated compensating devices such as choke valves, accelerator pumps, economizer jets etc., to achieve this objective.

It is now proposed to provide a simplified carburetor in which the air-fuel ratio may be readily controlled with a minimum amount of complicated structure. This is to be accomplished by providing a single fuel metering jet which is located in the air stream and is not only capable of supplying a charge suitable for normal operating conditions, but is also adapted to readily modify the air-fuel ratio of the charge under any circumstance which may necessitates such a change. It is proposed to place the fuel jet inside of a sleeve disposed in the charge forming passage so that the volume of fuel dicharged from the jet will be a function of the air flow through the sleeve. Both ends of the sleeve are open so that the air in the charge forming passage may flow therethrough. In addition, the sleeve is to be rotatably mounted, so that the axis of the sleeve may be rotated relative to the direction of the air flow in the charge forming passage. By changing the angular disposition of the sleeve, the air flow therethrough may be readily controlled. For example, if the axis of the sleeve is maintained parallel to the air flow, the air flow therethrough will be a maximum. On the other hand, if the axis of the sleeve is moved normal to the air flow, the air flow through the sleeve will be substantially zero. Since the fuel jet is locatedinside of this sleeve, the amount of air flowing past the jet and 2,845,257 Patented July 29, 1958 consequently, the amount of fuel atomized therein may be readily controlled by merely rotating the axis of the sleeve.

In the one sheet of drawings:

Figure l is a horizontal cross sectional view of a carburetor embodying the present invention.

Figure 2 is a vertical cross sectional view of the carburetor in Figure 1 taken substantially along the plane of line 2-2 in Figure 1.

Figure 3 is a view similar to Figure 2 but showing the carburetor in a different operating position.

Figure 4 is a cross sectional View similar to Figure 2 but showing the carburetor in still another operating condition.

Figure 5 is a cross sectional View taken substantially along the plane of line 5-5 in Figure 4.

Referring to the drawings in more detail, this invention may be embodied in any device suitable for mixing one or more secondary fluids with a primary fluid. In the present instance the invention is particularly adapted for installation in a carburetor l0 capable of atomizing and mixing a fuel with-air to form a combustible charge suitable for use in an internal combustion engine.

The present carburetor 10 is a so-called downdraft? type and includes a housing 12 having a charge forming passage 14 extending axially therethrough so that air may flow vertically downwardly therethrough. A throttle valve 16 may be disposed adjacent the downstream end of this passage 14 for controlling the volume of air flowing therethrough. The passage 14 may include a venturi 18 having a throat 24) of restricted cross sectional area. Thus whenever the air flows through the passage 14, a zone of partial vacuum will be created in and around the throat 20.

In order to mix the fuel with air as it flows through the passage 14 and thereby form a combustible charge, a fuel line 22 may extend transversely across the passage with a fuel metering jet 24 in the middle thereof. The fuel line 22 is preferably mounted in bushing 26 so that it may be rotated. This jet 24 is preferably disposed in the center of the passage 14 so that the quantity of fuel discharged from the jet 24 will be dependent upon the air pressure produced by the air flowing ther'epast.

A tubular member or sleeve 27 may be secured on the fuel line 22 so that it will be free to rotate with the fuel line 22. The sleeve 2'7 has a passage 28 extending completely therethrough so that both ends 30 and 32 will be open to allow the air to flow therethrough and also the fuel jet 24 may be disposed in the passage 28. By placing the lower end 32 of the sleeve 27 in thezone of partial vacuum, this vacuum will cause an increase in the volume of air drawn through the passage 28 in the sleeve 27. In addition, it is has been found preferable for the passage 28 through the sleeve 27 to include a second venturi 34 having a necked down throat 36 to form another zone of reduced pressure or a partial vacuum. It may thus be seen that by placing the jet 24 in the second throat 36 and placing the outlet end 32 of the sleeve 27 in the first throat 20, there will be a compounding of the vacuum adjacent the metering jet 24 with a corresponding increase in the accuracy with which the fuel may be metered.

As previously stated the sleeve 27 may be mounted on the fuel line 22 to rotate therewith. By offset in 37 the fuel line 22 the lower end of the sleeve 27 may be disposed in alignment with the axis of the line 22 and the zone of partial vacuum. Thus irrespective of the angular disposition of the fuel line 22 and the sleeve 27, the lower end of the venturi 34 will always be maintained in the throat vacuum.

By placing the sleeve 27 in axial alignment with the air flow as shown in Figures 1 and 2, the air entering the carburetor 1t) and flowing downwardly through the passage 14 will flow directly into and through the sleeve 27. As this air flows through the sleeve 27 it will atomize fuel from the fuel jet 24 and mix it with the air in the sleeve 27 and eventually with the air in the passage 14. Since the air flow through the sleeve 27 will be a maximum, the amount of fuel aspirated will be a maximum and so the charge will be the maximum richness. However, as the fuel line 22 is rotated, the angularity of the sleeve 27 with respect to the air flow changes, the percentage of air flow through the sleeve 27 will change. As the sleeve 27 reaches a position of 90, as seen in Figures 4 and 5, to the flow, the air will be flowing across each end 30 and 32 at right angles thereto. Consequently, the air pressures developed at each end 30 and 32 of the sleeve 27 will be substantially identical and there will be very little, if any, air flowing axially through the sleeve 27. It is therefore apparent that the amount of fuel aspirated from the fuel jet 24 will be substantially nil. However, by positioning the sleeve 27 at some intermediate position between these two extremes, as seen in Figure 3, the air flow through the sleeve 27 will vary from between zero and the maximum amount occurring when the sleeve 27 is in axial alignment. Thus, although the mixture produced in the sleeve 27 will be substantially constant, since the percentage of the air flowing through the sleeve 27 will vary, the air-fuel ratio of the over-all charge will vary. Accordingly, the air-fuel mixture may be readily controlled by the simple expedient of rotating the sleeve 27 with respect to the air flow.

If the carburetor is mounted on a conventional internal combustion engine, any suitable controls may be provided for adjusting the angularity of the sleeve 27. For example, the sleeve 27 could be manually rotated or controlled as some function of the throttle setting and/ or the intake manifold vacuum or by any other suitable means which will be indicative of the fuel requirements of the engine.

While but one embodiment has been illustrated and described, it will be apparent to anyone skilled in the art that the invention may be embodied in numerous other specific forms than that described without departing from the spirit thereof. It is, therefore, desired that the present embodiment be considered in all respects illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to determine the scope of the invention.

I claim:

1. A device for mixing a secondary fluid with a primary fluid comprising, a member having a passage extending therethrough for the flow of said primary fluid, a sleeve disposed in said passage and having a passage extending axially thereof, said sleeve member being adapted to rotate about a line normal to the axes of said passages for orienting the axis of said second passage to the direction of said flow of primary fluid through said first passage, said sleeve being radially spaced from the passage permitting the quantity of air flow through the first passage to be substantially unaffected by the axial orientation of the second passage, a jet disposed in said sleeve for discharging said secondary fluid into the passage in said sleeve for mixing with said primary fluid.

2. A device for continuously mixing a secondary fluid with a primary fluid comprising, a member having a passage extending therethrough for the flow of said primary fluid, a sleeve of substantially smaller diameter than said passage centrally disposed in said passage and having a passage axially therethrough with the opposite ends being open to allow a portion of said primary fluid to flow therethrough, means for rotating said sleeve about a line substantially normal to the axes of said passages and thereby vary the proportion of the primary fluid flowing through said second passage, the mass of air flow through the member passage being substantially unaffected by the angular position of said sleeve within the member passage, a jet disposed in said second passage for discharging said secondary fluid into said second passage in said sleeve for mixing with said primary fluid.

3. A device for continuously mixing a secondary fluid with a primary fluid comprising, a member having a passage extending therethrough for the flow of said primary fluid, a tube extending transversely of said passage normal to the axis of said passage and having a jet in the middle thereof, said tube being adapted to be connected to a source of said secondary fluid, a sleeve mounted on said tube and having an axial passage therethrough enclosing said jet, means for rotating said sleeve and tube for angularly orienting said second passage to the direction of flow of said primary fluid, said sleeve and axial passage being of substantially smaller cross sectional area than the member passage whereby the mass of air flow through the latter passage is substantially unaffected by the angular position of the sleeve.

4. A device for continuously mixing a secondary fluid with a primary fluid comprising, a member having a passage extending therethrough for the flow of said primary fluid, said passage including a portion of restricted cross sectional area adapted to create a zone of partial vacuum in said primary fluid as it flows therethrough, a sleeve of substantially smaller diameter than said passage disposed in said passage and having a passage therethrough with the opposite ends being open to allow a portion of said primary fluid to flow therethrough, a jet disposed in said second passage for discharging said secondary fluid therefrom, means for rotating said sleeve to vary the angularity of the two passages while retaining one of said open ends of said sleeve in said Zone.

5. A carburetor housing having a charge forming passage therethrough forming a venturi with a restricted throat for the flow of air therethrough, a fuel line extending transversely of said venturi throat, a sleeve of substantially smaller diameter than said passage carried on said fuel line and having a passage therethrough forming a second venturi having a restricted throat to allow a portion of the air in said first passage to flow therethrough, means for rotating said fuel line and said sleeve about the axis of said fuel line to change the angularity between the two passages and the proportions of the air flowing through the passages while retaining said lower end in said throat, said sleeve being mounted on said fuel line so that the lower end thereof terminates adjacent the rotative axis of the fuel line.

6. A carburetor as defined in claim 5 in which said fuel line includes a centrally offset portion to which said sleeve is mounted.

References Cited in the file of this patent UNlTED STATES PATENTS 1,737,496 Feroldi Nov. 26, 1929 1,863,402 Halm June 14, 1932 2,617,638 Udale Nov. 11, 1952 

